I recently bought an external Thunderbolt SSD from LaCie for my Mid-2011 iMac to use it as my boot drive (Mountain Lion). Now my problem is that after the Apple starting sound it always takes a lot of time (mostly 1 minute +) until the apple and the spinning wheel appear. After that booting time is just fine. I already cleared the PRAM. Does anybody know how to get the iMac recognize the SSD with the start volume faster (in the system preferences the SSD is set as the start volume)? Many thanks!